If you have get together, you could create a "work homework club" for your Sim. If she is able to accrue 500 points, then, you can click on "networked club" in the perks list, which promotes your Sim faster. My main Sim family is in a "work homework club," and I think they get promoted every 2 Sim days.
There are other "perks," such as "skill boosts," so cooking is included in that section of the perks list.
Before I got Get Together, they always did their work homework and went to work focused (the ideal mood for tech gurus) , and I think, it took them between 5 and 7 Sim days to get a promotion. My Sims are at the top of their careers (tech gurus) , so maybe that enables them to receive promotions faster, as well.